1. Field of the Invention
The present invention relates generally to processing of greensheets used to make ceramic substrates for microelectronic components.
2. Description of Related Art
In the ceramic electronics industry, multilayer ceramic (MLC) technology is typically used to create three-dimensional circuitry for microelectronic devices such as integrated circuits and ceramic capacitors. These three-dimensional circuitries are made by applying a conductive material in a circuit pattern on a ceramic/polymer composite sheet known as a greensheet.
A greensheet may have a number of via holes punched in it to allow vertical connection between the conductive material on adjacent sheets, whereby after the vias are punched in the sheets, the greensheet is screened and patterned by applying a conductive paste into the via holes and along the surface of the greensheet. A number of via punched greensheets are then stacked in a designated order and laminated together under appropriate heat and pressure to form a laminate which can be handled as a unified structure. The laminated ceramic/polymer composite is then heated to remove the polymer, and then heated to a higher temperature to sinter and densify the ceramic thereby forming the final MLC.
Over the years, future generations of MLC technology have developed to incorporate advanced technologies and groundrules, i.e., triple dense conductors, thin green sheets and large area greensheets. With these advanced technologies, as via diameters and the pitch associated therewith become smaller it is necessary to use thinner greensheets, and in particular, thinner sheets with large x-y dimensions. However, in the course of adopting such new technologies, greensheet stability has become a concern. In particular, the smaller vias and tighter grids pose radial error problems in punching and screening thinner greensheets, including deforming and embossing of the greensheet, and misalignment of the conductive vias and other features, thereby rendering the greensheet non-manufacturable.
As it is desirable that future via holes in thinner greensheets be punched and screened with a small radial error, a need continues to exist in the art for improved greensheets and methods of forming the same.